A DCAMM seminar will be presented by
Professor Paulo Martins
Instituto Superior Tecnico
University of Lisbon, Portugal
Abstract:
Fracture in sheet metal forming usually occurs as ductile fracture, rarely as brittle fracture, at the operating temperatures and rates of loading that are typical of real processes in two different modes: (i) tensile and (ii) in-plane shear (respectively the same as modes I and II of fracture mechanics).
The circumstances under which each mode will occur are identified in terms of plastic flow and ductile damage by means of an analytical approach to characterize fracture loci under plane stress conditions that takes anisotropy into consideration. Fracture loci is characterized by means of the fracture forming limit line (FFL) and by the shear fracture forming limit line (SFFL) in the fracture forming limit diagram (FFLD).
Experiments performed with single point incremental forming and double notched test specimens loaded in tension, torsion and in-plane shear give support to the presentation and allow determining the fracture loci of AA1050-H111 aluminium sheets with 1 mm thickness. The relation between fracture toughness and the fracture forming limits is also investigated by comparing experimental values of the strains at fracture obtained from a truncated conical part produced by single point incremental forming and from double notched test specimens loaded in tension.
Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
All interested persons are invited